Conventional aircraft are increasingly relying on an adequate electrical power distribution, including high power loads. Such electrical needs require the use of power electronics, such as power converters or choppers. An exemplary application of the high-power electric components is an electric taxiing system for an aircraft, using electric motors to drive wheels and power electronics to modulate electric signals supplied to the motors.
On airliners, electronic units are commonly installed in a dedicated avionic bay, which is fully equipped with necessary cooling provisions. However, due to a limited size of the avionic bay, and other constraints, such as wire lengths, supplementary power electronics used for the electric taxiing system have to be installed in other locations.
Due to their sensitivity to environmental conditions, such as temperature and humidity, a position within an environmentally-controlled part of a fuselage is mandatory for many of these components. This drastically reduces the available locations in the aircraft, as space within the fuselage is highly valuable. This is especially true for a retrofit aircraft, for which it is difficult to redesign an area to create room.
Referring now to FIGS. 1-3, sensitive elements are typically positioned within a controlled part of the fuselage to minimize a physical footprint, and less sensitive components are separately positioned outside of pressurized space. Various resulting electrical equipment 10 are shown in FIG. 1 and are generally installed in a fuselage 12 of an aircraft 14. One or more pieces of equipment 10 may be disposed near the Main Landing Gear Bay (MLGB) 16 or the Center Wing Box (CWB) 18. The installation of these equipment 10 could be done using common methods for system installation, such as fasteners.
High power electrical equipment 10 generate a relatively large amount of heat power (e.g., approximately 5 kW) inside the controlled part of the fuselage 12. This heat must be extracted to the exterior, for example, via an extraction duct 20 connected to each unit of the electrical equipment 10 and routed towards an outflow valve (not shown). A High Voltage Direct Current (HVDC) input cable 22 and HVDC output cable 24 can be connected to the units of the electrical equipment 10 for delivering power to other components in the aircraft 12, such as electric motors on the landing gear.
However, even though it is simple to install, this solution is not satisfactory due to some major physical drawbacks. For example, cooling fans (not shown) are loud, due to the adverse conditions in which they must operate: large pressure loss in a long duct, small installation volumes, and high air flows. Further, the installation of the duct within the space-constrained fuselage is very difficult and costly, especially in a retrofit aircraft.
Therefore, there is a need for developing an improved packaging having an efficient cooling system that is readily installable and reliable during operation without incurring high maintenance cost.